Twin diaphragm pump with stressrelieved diaphragms



F. L. GRANER Jan. 26, 1954 TWIN DIAPHRAGM PUMP WITH STRESS-RELIEVED DIAPHRAGMS Filed June 19, 1952 14 Sheets-Sheet 1 v Q u INVENTOR Frank L. Groner ATTORNEY F. GRANER 2,667,129

TWIN DIAPHRAGM PUMP WITH STRESS-RELIEVED DIAPHRAGMS Jan. 26, 1954 14 Sheets-Sheet 2 Filed June 19, 1952 INVENTOR Frank L. Gruner ATTORNEY Jan. 26, 1954 Filed June 19, 1952' F. L. GRANER 2,667,129

TWIN DIAPHRAGM PUMP WITH STRESS-RELIEVED DIAPHRAGMS 14 Sheets-Sheet 3- INVENTOR Fro nk L. Graner BY @MgX ATTORNEY F. L. GRANER Jan. 26, 1954 TWIN DIAPHRAGM PUMP WITH STRESS-RELIEVED DIAPHRAGMS F iled June 19, 1952 14 Sheet-Sheet 4 INVENTOR Fronk L. Gruner ATTORN Y Jan. 26, 1954 F. L. GRANER TWIN DIAPHRAGM PUMP WITH STRESS-RELIEVED DIAPHRAGMS 14 Shee'ts-Sheet 5 Filed June 19, 1952 Fig. 5.

INVENTOR Frank L. Groner ATTORNEY F. L. GRANER Jan. 26, 1954 TWIN DIAPHRAGM PUMP WITH STRESS-RELIEVED DIAPHRAGMS l4 Sheets-Sheet 6 Filed June 19, 1952 INVENTQR Frank L. Gruner ATTORNEY Jan. 26, 1954 TWIN DIAPHRAGM PUMP WITH STRESS- Filed June 19, 1952 14 Sheets-Sheet 7 INVENTOR Frank L. Groner ATTORNEY Jan. 26, 1954 F. GRANER 2,667,129

TWIN DIAPHRAGM PUMP WITH STRESS-RELIEVED DIAPHRAGMS Filed June 19, 1952 14 Sheets-Sheet 8 Y IIIIII;/

L L g t N NT INVENTOR Frank L. Gruner BYbg w ATTORN Jan. 26, 1954 F. L. GRANER 2,667,129

TWIN DIAPHRAGM PUMP WITH STRESS-RELIEVED DIAPHRAGMS Filed June 19, 1952 14 Shets-Sheet 9 Fig. 9.

INVENTOR Frank L, .Groner BYLJ, no

ATTOR Y F. L. GRANER Jan. 26, 1954 4 Sheets-Sheet 10 Filed June 19, 1952 INVENTQR Frank L Groner ATTORNEY Jan. 26, 1954 F. L. GRANER 2,667,129

TWIN DIAPHRAGM PUMP WITH STRESS-RELIEVED DIAPHRAGMS Filed June 19, 1952 v 14 sheets-sheet 12 I66 0 INVENTOR BY uFfllonlf L. Grones;

ATTORNEY Jan. 26, 1954 F. L. GRANER 2,667,129

TWIN DIAPHRAGM PUMP WITH STRESS-RELIEVED DIAPHRAGMS Filed June 19, 1952 14 Sheets-Sheet l4 INVENTOR T Frank L. Groner (Ll-bk 6X ATTORNEY Patented Jan. 26, 1954 TWIN DIAPHRAGM PUMP WITH STRESS- RELIEVED DIAPHRAGMS Frank L. Graner, Cold Spring, N. Y., assignor to The Dorr Company, Stamford, Conn., a corporation of Delaware Application June 19, 1952, Serial No. 294,393

Claims. 1

This invention relates to diaphragm type pumps suited for pumping abrasive slurries, chemical solutions, acids or other corrosive liquids, solidscarrying liquids, viscous pulps, or high density liquids or sludges derived, for example, from mechanical thickeners, gravity settlers or the like. However, the material being handled by these diaphragm pumps will herein be briefly referred to merely as slurry. Such a pump comprises as part of a pump chamber a deformable disc-shaped diaphragm member and actuating means for reciprocatively bulging the diaphragm inwardly and outwardly in alternation thereby drawing the liquid through an inlet check valve into the pump chamber during the suction stroke, and displacing or expelling liquid through an outlet check valve from the chamber during the delivery stroke of the pump.

Stroke adjusting devices are often provided in conjunction with the actuating means for varying the rate of delivery of the pump by varying the pump stroke even while the pump is running.

More in particular, this invention relates to diaphragm type pumps haveing stress-relieved diaphragms, and which will herein be termed stress-relieved diaphragm pumps. Such a pump may deliver against a desired pressure without having the diaphragm itself subjected to the stress resulting from such pressure. In such a pump the stress-relief for the diaphragm is due to diaphragm-actuating means which employ a pressure-transmitting fiuid medium or operating liquid to act upon the diaphragm for reciprocating the same. That is to say, the pressure of the operating fluid contacting the outside of the diaphragm balances the pressure of the fluid or slurry contacting the opposite or inner side of the diaphragm so that the diaphragm being confined between liquids from both sides is substantially completely stress-relieved while pumping.

The general purpose and character of stressrelieved diaphragm pumps will be more fully understood by their comparison with the more ordinary non-relieved type of diaphragm pump in which the diaphragm is actuated by a reciprocating rod attached directly to the diaphragm which is thus subject to the full pumping pressure and therefore to mechanical stresses and to a degree of stretching commensurate with such pressure. The non-relieved diaphragm pump is therefore not normally qualified to deliver against any appreciable pressure except at the price of correspondingly increased mechanical stresses and stretching and wear imposed upon the diaphragm with a corresponding concurrent reduction in volumetric pumping efiiciency. Therefore, such a pump is not well qualified to answer a requirement of furnishing what may be termed a metered disharge as visualized by this invention especially within wide limits of stroke adjustment and delivery rates, for example, between limits of zero and maximum. The requisites of a truly metered discharge as visualized by this invention are that the delivery rate adjusted to a value within such wide limits as zero and maximum should remain constant irrespective of variations in the discharge pressure or resistance or head against which the pump must operate.

By contrast, the stress-relieved diaphragm pump is capable of delivering against relatively high pressures, higher indeed than any pressures normally attainable by the non-relieved diaphragm pump, yet without impairment of volumetric pumping efiiciency, and it is adjustable as to delivery rates within a Wide range (as between zero and maximum) substantially without loss of volumetric efiiciency.

In a stress-relieved diaphragm pump of known construction the operating liquid was confined in a hydraulic operating chamber surrounding the outside of the diaphragm, and having associated therewith a reciprocating piston or plunger to act upon this confined volume of operating liquid in a manner to impart alternatingly suction and pressure to the diaphragm. In this Way the diaphragm was reciprocated through the intermediary of the operating liquid to effect pumping of the slurry. Consequently, adjustable control devices for varying the delivery rate of such a pump have been provided in direct association with the piston-actuating means for varying the piston stroke. Yet, while a variety of stroke adjusting devices either have been or could be employed with diaphragm pumps, their embodiment in a stress-relieved diaphragm pump unit carries with it certain disadvantages in the way of bulkiness and indeed in the way of certain structural as well as operational complications and design limitations especially when such a device is to permit adjusting of the piston stroke and of the delivery rate while the pump is running. For example, the stress-relieved diaphragm pump just outlined is equipped with stroke-adjusting devices for the piston or plunger capable of being manipulated only when the pump is stopped. Thus, a problem lies in providing a metering type diaphragm pump which is independent of and does not require any of the ceonventional stroke-adjusting devices, and whereby the inconvenience of stopping the pump is avoided in that adjustment can be effected wh le the pump is running.

Also in the above outlined stress-relieved diaphragm pump, since the volume of the pressure transmitting operating liquid is confined in a hydraulic operating chamber about the outer side of the diaphragm, it requires certain accessories in the nature of pressure relief devices as well as devices automatically supplying make-up operating liquid to the operating chamber, which devices represent structural as well as operational complications in the pump. The relief devices are employed to meet the emergency or the possibility of a clogged discharge pipe, whereas the make-up device should function to replace operating liquid which may be lost from the chamber through the relief device or otherwise. Thus, another problem lies in avoiding the need of employing such relief and make-up devices.

Still another drawback in the above outlined stress-relieved diaphragm pump lies in that they require expensive and bulky motor driven reduction gearing for actuating the piston or plunger of the hydraulic operating chamber. Hence, it is another problem to provide a stressrelieved diaphragm pump unit without the need for such gearing.

Therefore, it is among the objects of this invention to provide a stress-relieved diaphragm pump unit which meets the metering requisites above set forth in that it has a uniformly high volumetric eificiency over a wide range of delivery rates as between zero and maximum and maintains the adjusted delivery rate substantially constant in spite of variations of or fluctuations in the delivery pressure; which is relatively simple and compact even though capable of relatively high maximum delivery rates; which is accurately and sensitively controllable in a simple and convenient manner as to the adjustment of the metered discharge rate even while the pump is running; which is immune to the effects of possible clogging or obstruction of the discharge pipe without involving the use of the conventional relief and make-up devices above referred to; and which provides diaphragm actuating means requiring none of the conventional gearing above referred to.

A known construction of a stress-relieved type of diaphragm pump provides for such a pump that is double acting in that a single actuating plunger or piston reciprocating between a pair of hydraulic operating chambers and diaphragms exerts during one stroke hydraulic pressure upon the diaphragm of one chamber while by the same token applying suction to an opposite diaphragm, and vice versa, during the succeeding stroke. Since such a pump requires and is provided with the aforementioned pressure-relief devices and water make-up devices, as Well as with a prime mover or motor and gearing for reciprocating the actuating piston, it is another object to provide an improved double-acting pump free from such drawbacks.

These objects are attained in a double-acting pump unit in which the two diaphragms in a pump housing are mechanically and kinematically so interconnected as to move in unison, and they are furthermore operationally connected with a spool type control valve means whereby hydraulic operating water from apressure water supply is admitted to one of the hydraulic actuating chambers while operating water is being released from the opposite operating chamber, and vice versa, as the valve means operate through a pumping cycle. In fact, the control valve means according to this invention comprises a primary or spool valve member and a secondary or slidable sleeve valve member within which the spool operates, the sleeve member being provided with an arrangement of port openings bearing certain cooperative relationships with respect to the spool. The spool and the sleeve are movable axially relative to one another, the sleeve in turn being movable axially in a valve housing which is fixedly associated with the pump housing. The sleeve or secondary valve member is kinematically connected with both diaphragms so as to move in unison therewith, whereas the spool or primary valve member is controllably reciprocatable by a suitable drive.

The controlled movement of the spool within the sleeve member admits operating water under pressure to one of the hydraulic operating chambers while releasing such water from the other chamber, and vice versa, through a pumping cycle, thereby reciprocating the diaphragms.

In other words, the valve-controlled operation of the pump is initiated and maintained by the movement of the spool relative to the sleeve, which through control of operating water actuates the diaphragms which in turn move the valve sleeve member in unison therewith. The net result is that the movements of the sleeve and of the diaphragms in unison substantially follow and reflect the controlling movement of the spool so that varying the stroke of the valve spool member will correspondingly a'rlect or influence the movement of the diaphragms and the pumping rate.

In fact, this follow-up relationship between the sleeve member and the spool member enables the pump to adjust itself automatically to variations of discharge head or back pressure at the discharge end of the pump in a manner whereby the pump will automatically maintain a predetermined and adjusted rate of metered discharge. Indeed, with every change, namely increase or decrease in the magnitude of the discharge head or back pressure this control valve will respond in a compensatory fashion by proportionately decreasing or increasing the throttling effect or pressure drop of the pressure water being admitted through the control valve to the respective hydraulic operating chambers. That is to say, whenever the back pressure at the discharge end of the pump increases, it will momentarily retard the movement of the diaphragm and thereby equally retard the movement of the sleeve member with which it is kinematically coupled. Thus, since the spool member continues at its adjusted rate of speed and reciprocatory frequency, there will occur a corresponding slippage between the sleeve member and the spool member, the amount of that slippage being sufficient to increase the effective through-flow area of the port openings in the sleeve member until there is attained a decrease in pressure drop across the through-flow passages or port openings, substantially proportionate to the aforementioned increase in back pressure at the discharge end of the pump. I-Ience, as a result of such load induced slippage between the telescoping moving parts of the control valve there is admitted to the respective hydraulic operating chambers a relatively increased water pressur sufficient to balance the increased pumping pressure. Correspcndingly, with a decrease of back pressure at the discharge end of the pump, the resultant slippage of the sleeve member relapressure is in balance with the pumping pressure. 7

In this way the pump automatically absorbs any fluctuations in discharge back pressure substantially without effecting the adjusted rate of metered discharge.

More particularly, to attain the aforementioned objects a double-acting pump according to this invention comprises two pumping sections side by side constituting a common substantially cylindrical housing. Each pumping section or half of this common housing comprises a hydraulic operating chamber at one side of one diaphragm, and a slurry pumping chamber proper at the other side of that diaphragm. Thus, the two hydraulic operating chambers may constitute the outer ends of the common housing, while the two pumping chambers constitute the intermediate portion of this common housing; each hydraulic operating chamber has a port or connection with the spool type control valve means, allowing hydraulic operating water to enter as well as leave the operating chamber in the course of a pumping cycle of that pumping section, whereas each pumping chamber has a suitable check valve for slurry inlet as well as a checi: valve for slurry outlet. The diaphragms reciprocate in unison due to a link construction operatively interconnecting them. The spool type control valve means comprises a cylindrical housing having a supply connection for pressure water to be controllably admitted through the valve means to respective operative chamhers in alternation, and a spent water discharge connection for such operating water to be controllably released and displaced from respective hydraulic operating chambers through the valve means incident to the operation of the spool member and the sleeve member relative to one another and relative to the valve housing.

According to one feature, pressure water for the hydraulic operating chambers is supplied through the valve means by a centrifugal servopump while spent water from the operating chamber passing through the valve means returns to the suction side of the pump, so that the diaphragm pump proper together with the servo-pump and various passages leading to, through, and from the control valve means between the pumps constitute a closed circulating system for the operating water. Moreover, the suction end of the servo-pump communicates with an expansion chamber or reservoir which supplies the need for or absorbs the excess of operating water, thus dispensing with the aforementioned relief devices and make-up devices. In case the discharge of the diaphragm pump should get clogged or blocked, relief is automatically provided with the centrifugal pump merely continuing to run against what is the normal maximum pressure producible by the pump.

According to another feature, the controlling reciprocating motion of the valve spool member is imparted thereto by means of a motorized servo-drive unit embodying stroke adjustment means. Further particularized, a servo-drive unit herein proposed lends itself to efiecting the stroke adjustment by remote control.

Other features lie in the manner in which the diaphragms are operatively interconnected for movement in unison, as well as kinematically connected to the valve sleeve member, whereby the diaphragms move in unison with the sleeve member. According to one such feature, each diaphragm has a stem pointing outwardly to and passing through a respective end of the pump housing and in sealed relationship thereto. The end of each such diaphragm stem has pivotal connection with the end of a swingable arm fixed upon a rocker shaft that is horizontal and extends transversely of the longitudinal horizontal axis of and through the pump housing with one end of the rocker shaft extending outwardly exposed from the housing and in sealed relationship therewith; the exposed ends of both rocker shafts are operatively interconnected by motion transmitting means so that thereby both diaphragms must move simultaneously. Furthermore, the exposed end of one of the rocker shafts has motion transmitting means operatively or kinematically connecting it with the valve sleeve member so that the diaphragms will move in unison therewith.

According to a more specific structural feature, this pump comprises a substantially cylindrical pump housing with a horizontally extending longitudinal axis and having a removable closure plate at each end. The controlling spool valve unit is mounted upon and carried by the pump housing although somewhat at one side thereof and with its longitudinal horizontal axis parallel to that of the pump housing. The two rocker shafts are mounted in a top portion of the pump housing to extend horizontally and transversely of the horizontal longitudinal axis of the pump housing and so that the exposed ends of these rocker shafts are disposed adjacent to respective ends of the spool valve unit. The motion transmitting means between the exposed ends of these two rocker shafts comprise an actuator arm extending from each exposed end and fixed thereto, both actuator arms being downwardly coextensive and being interconnected at their lower ends by a horizontally extending link member. One of these downward actuator arms has what is in effect an upward extension or upward actuator arm for operatively engaging the valve sleeve member; that is, the sleeve member has a stem portion extending horizontally and axially through one end of the valve housing in watersealed relationship therewith, the sleeve stem portion having operative connection with the upward actuator arm, so that the sleeve member will move in unison with the diaphragms. The valve spool member has a stem portion extending horizontally and axially through the opposite end of the valve housing in water-sealed relationship therewith, which spool stem portion has operative connection with the aforementioned servo drive unit which in turn is mounted upon and supported by the pump housing.

Other features lie in the structural organization and mutual structural relationship of the main component portions of this pump unit in the special construction of casting representing some such component portions, and in the manner in which these castings are structurally associated with one another.

Still other features reside in the particular construction of the spool type control valve unit. One such feature lies in the fact that the valve automatically presents additional flow passage or port area for the discharge therethrough of spent water from the operating chambers; in this way the back pressure or flow resistance to the discharge of spent water is minimized. Another feature lies in having the spool valve member so shaped as to accentuate the difierential of comparative flow resistance across the pressure port area and the discharge port area.

In summary, this invention provides a double acting stress-relieved diaphragm pump unit in which pressure water is supplied to the hydraulic operating chamber by a centrifugal servo-pump with spent operating water returning to the suction end or low pressure side of the pump. Control valve means in the nature of a spool valve unit are functionally interposed between the servo-pump and the diaphragm pump proper, whereby pressure water is supplied at a controlled rate to the one diaphragm while spent water is released from the other diaphragm, and vice versa, in the course of a pumping cycle. The control valve unit comprises a spool valve member slidable in a sleeve member and both the spool and the sleeve being slidable in and relative to a valve housing. Each of the operating chambers has a two-way passage connecting it with the valve housing while the servo-pump has a pressure and a suction connection with the valve housing, all so disposed that the operation of the valve unit will effect the above mentioned pumping cycle of this double acting diaphragm pump. The valve unit operates to that effect by reason of the diaphragms being operatively linked to each other as well as to the sleeve member so that they all move in unison, while servo-drive means impart to the spool member reciprocations of an adjusted or adjustable length of stroke of an adjustable speed. An expansion chamber or reservoir is provided to communicate with the suction side of the servopump.

In the drawings, Figure 1 is a highly diagrammatic sectional view of the stress-relieved diaphragm pump unit showing operating conditions during the stroke in one direction of the pumping cycle.

Figure 2 is a diagrammatic view similar to Figure 1, showing conditions during the opposite stroke of the pumping cycle.

Figure 3 is a less diagrammatic view of the pump unit somewhat more explicit with respect to control mechanism and linkage, but otherwise corresponding to operating conditions shown in the Figure 1.

Figure 4 is a diagrammatic view of the pump unit similar to that of Figure 3, but corresponding to the operating condition shown in Figure 2.

Figure 5 is a perspective view of the pump unit structurally more fully developed with the diaphragm pump itself shown in part section and with part of the unit drawn apart.

Figures 6 to 9 show various views of the pump unit structurally more fully executed than the unit shown in Figure 5; that is, Figure 6 is a top view of the pump unit including a motorized servo-pump and a motorized drive unit for the control valve; Figure 7 is a. side view of the pump unit taken on line I---'! of Figure 6; Figure 8 is a part sectional end view of the pump taken on line 88 of Figure 6; Figure 9 is a vertical sectional view or the pump taken on line 9--9 of Figure 8.

Figure 10 is a detail section taken on line l0! 0 of Figure 8 to show a view upon the discharge end of the diaphragm pump proper.

Figure 11 is a detail sectional view taken on line llll of Figure 8, to show a view upon the flanged top of the housing of the diaphragm pump.

Figure 12 is a detail sectional view taken on line |2|2 in Figure 8, to show a horizontal section of the control valve housing.

Figures 13 and 14 are enlarged perspective views of the telescopically moving parts of the spool type control valve; Figure 13 showing the spool valve member; Figure 14 showing the sleeve valve member.

Figure 14 shows a developed internal view of the valve housing.

Figure 15 is a perspective view of the valve housing with a view taken approximately in the direction indicated by arrow Q in Figure 6, and part sectioned vertically as well as horizontally and also transversely halved with the halves drawn apart.

Figure 16 is a section taken on lines itl8 of Figure 6.

Figure 17 is a section taken on line lL-l'l of Figure 16 or of Figure 12, or of Figure 6.

Figure 18 is a section taken on line i8l8 of Figure 16 or of Figure 12, or of Figure 6.

Figures 19 and 20 are simplified diagrammatic representations of the characteristic operating conditions of the control valve in terms of operating positions of the ports of the slidable sleeve member relative to the connections leading to and from the fixed valve housing, with the ports developed in a manner similar to that of Figure 14 Figures 21 and 22 are valve operating views corresponding to those of Figures 19 and 20 although indicating structural evolution such as embodied and shown in the valve housing of Figures 15, 16, 1'7 and 18.

Figures 23 and 24 are enlargements of the longitudinal sectional view of the spool valve shown in Figure 9, although showing more clearly the details of the spool member of Figure 13 and of the sleeve member of Figure 14 as well as their dimensional relationship with Figure 23 corresponding to the operating condition of Figure l and Figure 24 corresponding to the operating condition of Figure 2.

The basic component portions of sections of the pump unit as viewed in terms of the diagrammatic Figs. 1 and 2 are represented by a diaphragm pump section P proper, a control valve section V, a servo-drive section D, and a pressure water supply section S, all of these component sections B, V, D, S, being defined more clearly with respect to one another by respective dotand-dash outlines or boxes surrounding them.

The pump section P comprises a double-acting diaphragm ump having a housing is which has a horizontally extending body portion I l and end portions :2 and i3, and which housing is subdivided by a transverse central partition wall l0 defining a pair of housing sections l4 and I5. Each of these sections it and 15 in turn is subdivided by a pump diaphragm into a pump chamber proper and. a hydraulic operating chamber. That is to say, the housing section i4 is divided by a diaphragm 56 into a pumping chamber H disposed at the inner side of the diaphragm and a hydraulic operating chamber 18 disposed at the outer side of this diaphragm; similarly, the housing section I5 is divided by a diaphragm 19 into a pumping chamber 20 disposed at the inner side of the diaphragm and a hydraulic operating chamber 2! disposed at the outer side of the diaphragm. A two-way passage 22 connects the hydraulic operating chamber IS with the left-hand portion of the housing 3'! of control valve section V, while another two-way passage 23 connects the hydraulic operating chamber 2i with the right-hand portion of the housing 31 of control valve section V. The pumping chamber ii is connected by a two-way passage 24 with a valve head 25 comprising an inlet ball check valve 25 and an outlet ball check valve 27; similarly, the pumping chamber 26 is connected by a two-way passage 28 to a valve head 29 comprising an inlet check valve 3E3 and an outlet check valve 3 l.

The diaphragm it has a stem 32 extending horizontally and outwardly from it while the diaphragm [9 has a similar stem 33 extending in the opposite direction. For diagrammatic purposes both stems 32 and 33 are shown to extend as through each end of the pump housing H3 and in water-sealed relationship therewith so that the outer ends 3 2 and 35 of respective dia phragm stems can be operatively interconnected as by an interconnecting member or rod 35 whereby both stems 32 and 33 and their diaphragrns i6 and 59 are adapted to move in unison.

The control valve unit V according to diagrammatic Figures 1 and 2 comprises a valve housing 3'! horizontally coextensive with the pump housing I ii and having horizontal body portion 38 and end portions 39 and MI. This valve unit V is of the spool and sleeve type comprising a sleeve member 4| having sliding fit in the valve housing and being horizontally slidably movable therein and a spool member 42 having sliding fit within the sleeve member and being horizontally slidably movable therein. The slidable spool member 42, the slidable sleeve member 3!, and the fixed valve housing 37 are all horizontally coaxial and their common horizontal axis is parallel to that of the pump housing id. The joint movement of the diaphragm i and it is kinematically coupled with the movement of the sleeve member 4| in that there is provided a double-armed vertical lever 43 having its fulcrum point at 44 fixed with respect to the pump housing H3 and as well as with respect to the valve housing 3'!. The lever 43 has an upwardly extending arm 13* to connect operatively with the end 35 of diaphragm stem 33, and it has a downwardly extending arm 43* of lever d3 connecting operatively with the sleeve member ll in that this sleeve member has a stem portion 45 extending through the end portion 4B of the valve housing in water-sealed relationship therewith. as the diaphragms It and i9 reciprocate, the sleeve member ll will reciprocate in unison therewith although in relatively opposite directions. The spool member 42 is to be reciprocated independently by means of the servo-drive mechanism D which connects operatively with a stem portion 16 of spool member 42 and extends through the end portion 39 of the valve housing and has water-sealed relationship therewith. It is thus that the diaphragms it and it will substantially follow and reflect the primary or pilot or leading movements of the reciprocating spool member 32 in a manner more fully described further belowv However, there will now first be given a more detailed description of the parts of the valve unit itself, namely of the interior of the valve housing with respect to certain recesses or chambers therein, of the sleeve member ll with respect to certain port openings therein, and of the spool member 42 with respect to certain flow controlling and flow directing portions thereof. The interior of the valve housing 3'! presents a central annular recess 4! for receiving a steady supply of pressure water as through supply connection or passage 48, the recess l? therefore constituting a stationary pressure supply chamber from which pressure water can be directed alternatingly to respective hydraulic operating chambers l8 and 2|. To the left of recess or pressure chamber 41 there is provided an annular recess 49 communicating through two-way passage 22 with the hydraulic operating chamber 18, while to the right of pressure supply chamber 4! there is provided an annular recess 50 similar to recess 49 although communicating with the hydraulic operating chamber 2| by Way of two-way passage Both recesses 49 and 5t constitute transfer chambers in that through them hydraulic operating water passes to and from respective hydraulic operating chambers 18 and 2 l Furthermore, to the left of transfer chamber 49 at the end of the valve housing 8'! there is provided a recess 5|, constituting a discharge chamber for spent hydraulic operating water released from operating chamber lil which released spent water must pass through discharge chamber 5! in order to reach a discharge passage 52 leading from the valve housing 37. Correspondingly, at the opposite end of the valve housing 3'! there is provided a recess 53 constituting a discharge chamber for spent hydraulic operating water released from operating chamber 21 and dischargeable from the chamber 53 through a discharge passage 56 leading therefrom.

The sleeve member 4| has sets of port openings through which the various interior recesses or stationary chambers 47, 49, 5t], 5!, 53 of the valve housing may communicate with the interior of the sleeve member 4!, these sets of port openings being so arranged that with the reciprocation of the spool member 42 they will control and direct the passage of hydraulic operating water to and from the hydraulic operating chambers l8 and 2! in a manner whereby there is effected the desired reciprocation of the diaphragms l6 and E8 in unison with the reciprocation of the sleeve member 4! and substantially in tune with the reciprocation of the spool member 42.

Such an arrangement of port openings comprise one or a set of port openings 55 communicating with the stationary pressure chamber t'l during all phases of reciprocation of the sleeve member 3!; one or a set of port openings 55 associated with one or a set of port openings 5? spaced to the left therefrom, both openings 55 and 51 communicating with the stationary transfer chamber 49 during all phases of reciprocation of the sleeve member 4|; and finally one or a set of port openings 58 associated with one or a set of port openings 59 spaced outwardly therefrom, both sets of openings 56 and 59 communicating with the stationary transfer chamber 59 during all phases of reciprocation of the sleeve member 5!. The right-hand end of the sleeve member 4! is closed partially by virtue of its connection with the stem portion 4-5 providing for a set of one-way transfer passages 55* for releasing therethrough spent hydraulic discharge water from the interior of the sleeve into the discharge chamber 53 and thence into the discharge passage E l.

The spool member 42 comprises a spool head 5 Of the length (Z) having a sliding fit within ii the sleeve member (ii, and formed with sliding cylindrical portions for controlling and directing the passage of hydraulic operating water through the respective port openings of the sleeve member ll incident to the reciprocation of the spool member 62 relative to the movement of the sleeve member Al. That is to say, the spool head 6!! is formed at its outer or right-hand end with a wide port closure portion 6! substantially defined by a cylindrical outer contour of the height in and provided with horizontal relief passages 62. A similar port closure portion 63 is formed at the opposite end of the spool head, which closure portion has horizontal relief passages 64. Spaced inwardly from the port closure portion 63 is a narrow and solid flow-controlling and directing portion 65 resembling a circular rib portion defined by an outer cylindrical contour of the height ha, so that the closure portion 63 and the rib portion 65 form between them an annular narrow reciprocatable transfer chamber 66 of the width 101. A similar flow controlling and directing rib portion 6'! is provided symmetrically with respect to the rib portion 85, so that there is formed between closure portion 6! and rib portion 67 a narrow reciprocatable transfer chamber 68 of a width an equal to that of the other narrow reciprocatable transfer chamber 66. Thus, there is formed between the rib portions 65 and El a wide reciprocatable pressure supply chamber 69 which communicates at all times through port openings 55 with the stationary pressure supply chamber 41.

The pressure supply section S of the pump unit comprises a centrifugal servo-pump '18 having its pressure end Hi connected to the pressure supply passage 48 leading into the valve housing 31 of valve unit V, and having its suction end it connected as by a header H to both spent water discharge passages 52 and 54 leading from respective ends of the housing 31 of valve unit V. A reservoir or expansion chamber 52 is also connected to the suction end of the servo-pump by way of header 1! The servo-drive mechanism D is represented in Figures 1 and 2 merely by a driven eccentric member 73 which through a slide block M engaging a vertical guide member reciprocates the spool member 42.

Figures 1 and 2 illustrate the operation of the pumping cycle as effected by the reciprocatory pilot movement of the driven valve spool member 42. That is to say, Figure 1 shows the condition under which the diaphragm pump performs the one stroke of the pumping cycle, N

namely in the direction of arrows A, whereas Figure 2 shows the condition under which the diaphragm pump performs the opposite stroke of the pumping cycle, namely in the direction of arrows A1. It should be noted that during both pumping strokes, in other words that throughout the entire pumping cycle, the full operating water pressure is present and available in the reciprocatable pressure supply chamber 59 because of the constant communication of that chamber through port openings 55 with the stationary pressure supply chamber ll and thus with the pressure end of the centrifugal servo-pump 18.

According to Fig. 1, if the eccentric member 13 rotates in the direction of arrow B moving the spool member 42 from dead center point 01 towards dead center point 02, its movement relative to the sleeve member 41 is such that the port openings 58 in the sleeve member become partly and sufficiently uncovered by the movei2 ment of the spool member 42 leading the movement of the sleeve member 4!, thereby admitting pressure water in the direction of arrows C from the reciprocatable pressure supply chamber 553 through port openings 58, stationary transfer chamber 56, and passage 23 into the hydraulic operating chamber 2|, although the associated port openings 59 remain closed during this stroke.

At the same time and by the same token (during the Figure 1 leftward stroke of the pump) the port openings 56 as well as the openings 5'! are uncovered to the same extent that the openings 58 are uncovered, yet in the opposite sense whereby spent hydraulic operating water is released in the direction of arrows E from the operating chamber l8 through passage 22, transfer chamber 49, then simultaneously through both sets of port openings 56 and 5'1, through the reciprocatable transfer chamber $6 and the 7 transfer passage E4 into the stationary discharge chamber 5| whence the spent operating water leaves the valve housing by way of the discharge passage 52 leading to the suction end of the servo-pump 70 by way of header 7!. Thus, the spool member s2 in moving from dead center point 01 to dead center point 02 slightly leads the movement of the sleeve member 4i while effecting the pump stroke in the leftward direction of arrow A, thereby effecting the delivery of pumped slurry from pump chamber 20 through check valve 3 l, at the same time drawing slurry through the check valve 26 into the pumping chamber l1.

Considering the Figure 2 operating condition of the pump unit, if the eccentric member 13 continues rotating so that the movement of the spool member 42 is reversed and therefore moves from dead center point 02 back to dead center point 01 in the direction of arrows F, this will reverse the flows through respective sets of port openings in the sleeve member, again as the movement of the spool member 42 slightly leads the movement of the sleeve member ii in the direction of arrows F, while effecting the pump stroke in the rightward direction of arrows A1.

That is to say, the Figure 2 rightward stroke of the diaphragm pump is effected by pressure water obtained from the reciprocatable supply chamber 69 and being admitted through port openings 56 being partly uncovered, and through the stationary transfer chamber 49, and through the passage 22 into the hydraulic operating chamber l8, while the associated port openings 51 remain closed. At the same time and by the same token, the port openings 53 and 59 become uncovered to the same extent as the openings 5'5 are uncovered although in the opposite sense and in such a way that spent operating water is released from the hydraulic operating chamber 2! by way of the passage 23, stationary transfer chamber 59, port openings 53 and 59, reciprocatable transfer chamber 68, transfer and relief passage 62 and 65, into the discharge chamber 53, and hence by way of discharge connection 54 and header "H to the suction end Hi of servopump 10.

In this way, Figures 1 and 2 illustrate the pumping cycle whereby the diaphragms i6 and 19 are actuated and reciprocated against the pump delivery pressure and in tune with those reciprocations which are controllably imparted to the spool member 42. The pump unit is started by starting the servo-pump so as to provide and supply a steady available hydraulic 

